libavformat/rtpdec_mpegts.c

   1 /*
   2  * RTP MPEG2TS depacketizer
   3  * Copyright (c) 2003 Fabrice Bellard
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "mpegts.h"
  23 #include "rtpdec_formats.h"
  24
  25 struct PayloadContext {
  26     struct MpegTSContext *ts;
  27     int read_buf_index;
  28     int read_buf_size;
  29     uint8_t buf[RTP_MAX_PACKET_LENGTH];
  30 };
  31
  32 static PayloadContext *mpegts_new_context(void)
  33 {
  34     return av_mallocz(sizeof(PayloadContext));
  35 }
  36
  37 static void mpegts_free_context(PayloadContext *data)
  38 {
  39     if (!data)
  40         return;
  41     if (data->ts)
  42         ff_mpegts_parse_close(data->ts);
  43     av_free(data);
  44 }
  45
  46 static int mpegts_init(AVFormatContext *ctx, int st_index, PayloadContext *data)
  47 {
  48     data->ts = ff_mpegts_parse_open(ctx);
  49     if (!data->ts)
  50         return AVERROR(ENOMEM);
  51     return 0;
  52 }
  53
  54 static int mpegts_handle_packet(AVFormatContext *ctx, PayloadContext *data,
  55                                 AVStream *st, AVPacket *pkt, uint32_t *timestamp,
  56                                 const uint8_t *buf, int len, uint16_t seq,
  57                                 int flags)
  58 {
  59     int ret;
  60
  61     // We don't want to use the RTP timestamps at all. If the mpegts demuxer
  62     // doesn't set any pts/dts, the generic rtpdec code shouldn't try to
  63     // fill it in either, since the mpegts and RTP timestamps are in totally
  64     // different ranges.
  65     *timestamp = RTP_NOTS_VALUE;
  66
  67     if (!data->ts)
  68         return AVERROR(EINVAL);
  69
  70     if (!buf) {
  71         if (data->read_buf_index >= data->read_buf_size)
  72             return AVERROR(EAGAIN);
  73         ret = ff_mpegts_parse_packet(data->ts, pkt, data->buf + data->read_buf_index,
  74                                      data->read_buf_size - data->read_buf_index);
  75         if (ret < 0)
  76             return AVERROR(EAGAIN);
  77         data->read_buf_index += ret;
  78         if (data->read_buf_index < data->read_buf_size)
  79             return 1;
  80         else
  81             return 0;
  82     }
  83
  84     ret = ff_mpegts_parse_packet(data->ts, pkt, buf, len);
  85     /* The only error that can be returned from ff_mpegts_parse_packet
  86      * is "no more data to return from the provided buffer", so return
  87      * AVERROR(EAGAIN) for all errors */
  88     if (ret < 0)
  89         return AVERROR(EAGAIN);
  90     if (ret < len) {
  91         data->read_buf_size = FFMIN(len - ret, sizeof(data->buf));
  92         memcpy(data->buf, buf + ret, data->read_buf_size);
  93         data->read_buf_index = 0;
  94         return 1;
  95     }
  96     return 0;
  97 }
  98
  99 RTPDynamicProtocolHandler ff_mpegts_dynamic_handler = {
 100     .codec_type        = AVMEDIA_TYPE_DATA,
 101     .parse_packet      = mpegts_handle_packet,
 102     .alloc             = mpegts_new_context,
 103     .init              = mpegts_init,
 104     .free              = mpegts_free_context,
 105     .static_payload_id = 33,
 106 };